Neuronal RING finger protein 11 (RNF11) regulates canonical NF-κB signaling

• Type of Material: Article
• Authors: Elaine L. Pranski, Emory University; Nirjari V. Dalal, Emory University; Jeremy Hartford Herskowitz, Emory University; Adam L. Orr, Emory University; Leah Anderson Roesch, Emory University; Jason Jon Fritz, Emory University; Craig Heilman, Emory University; James J Lah, Emory University; Allan I Levey, Emory University; Ranjita Betarbet, Emory University
• Language: English
• Date: 2012-04-16
• Publisher: BioMed Central
• Publication Version: Final Published Version
• Copyright Statement: © 2012 Pranski et al; licensee BioMed Central Ltd.
• License: Creative Commons Attribution 2.0 Generic
• Final Published Version (URL): http://www.jneuroinflammation.com/content/9/1/67
• Title of Journal or Parent Work: Journal of Neuroinflammation
• ISSN: 1742-2094
• Volume: 9
• Issue: 67
• Start Page: 2
• End Page: 16
• Grant/Funding Information: We thank the National Institutes of Health through Alzheimer’s Disease Research Center grant AG025688, National Institute of Environmental Health Sciences (NIEHS) grant ES015777 (to RSB), NIEHS grant ES012870 (to ELP) and National Institute of Neurological Disorders and Stroke (NINDS) grant NS007480 (to ELP).; This research project was supported in part by the viral vector and microscopy cores of the Emory Neuroscience NINDS Core Facilities grant P30NS055077.
• Research Categories: Biology, Neuroscience

Abstract

Background The RING domain-containing protein RING finger protein 11 (RNF11) is a member of the A20 ubiquitin-editing protein complex and modulates peripheral NF-κB signaling. RNF11 is robustly expressed in neurons and colocalizes with a population of α-synuclein-positive Lewy bodies and neurites in Parkinson disease patients. The NF-κB pathway has an important role in the vertebrate nervous system, where the absence of NF-κB activity during development can result in learning and memory deficits, whereas chronic NF-κB activation is associated with persistent neuroinflammation. We examined the functional role of RNF11 with respect to canonical NF-κB signaling in neurons to gain understanding of the tight association of inflammatory pathways, including NF-κB, with the pathogenesis of neurodegenerative diseases. Methods and results Luciferase assays were employed to assess NF-κB activity under targeted short hairpin RNA (shRNA) knockdown of RNF11 in human neuroblastoma cells and murine primary neurons, which suggested that RNF11 acts as a negative regulator of canonical neuronal NF-κB signaling. These results were further supported by analyses of p65 translocation to the nucleus following depletion of RNF11. Coimmunoprecipitation experiments indicated that RNF11 associates with members of the A20 ubiquitin-editing protein complex in neurons. Site-directed mutagenesis of the myristoylation domain, which is necessary for endosomal targeting of RNF11, altered the impact of RNF11 on NF-κB signaling and abrogated RNF11’s association with the A20 ubiquitin-editing protein complex. A partial effect on canonical NF-κB signaling and an association with the A20 ubiquitin-editing protein complex was observed with mutagenesis of the PPxY motif, a proline-rich region involved in Nedd4-like protein interactions. Last, shRNA-mediated reduction of RNF11 in neurons and neuronal cell lines elevated levels of monocyte chemoattractant protein 1 and TNF-α mRNA and proteins, suggesting that NF-κB signaling and associated inflammatory responses are aberrantly regulated in the absence of RNF11. Conclusions Our findings support the hypothesis that, in the nervous system, RNF11 negatively regulates canonical NF-κB signaling. Reduced or functionally compromised RNF11 could influence NF-κB-associated neuronal functions, including exaggerated inflammatory responses that may have implications for neurodegenerative disease pathogenesis and progression.